The present invention relates to an elevator control apparatus for managing a plurality of elevator cages in a group and, more particularly, to an elevator control apparatus for moving a free cage to an optimum stand-by floor at the time when a cage is free.
Recently, in an elevator control apparatus for group supervising a plurality of elevator cages, a microcomputer is employed to process a large amount of information and arithmetic operations, thereby realizing a precise control.
Generally, an elevator cage pauses at a floor after the cage responds to the final call, and enters a stand-by state until a hall call is then assigned to the cage, thereby becoming a free cage. Such a free cage usually occurs in an ordinary time zone which is not congested. However, it is not always effective for the free cage to stand by at the final respons floor as it is.
Therefore, when all the elevator cages become free and a predetermined time is then elapsed in a prior-art elevator control apparatus, a method of dispersively standing by the respective cages at predetermined floors is employed.
There is also considered a method of determining effective stand-by floors for the free elevator cages in accordance with learned data as disclosed in Japanese Laid-open Patent Application No. 60-209475. In this case, the stand-by floors are determined as floors having higher priority order of many traffic demands on the basis of main floor, upper floor or learning result.
However, although passenger demand can be predicted to a certain degree from a learning result, the congestion of the passengers does not always become as predicted. Since an accidental congestion of passengers cannot be predicted, the timing of determining stand-by floors or generating a stand-by command is not always optimum under the circumstances of all the time points.
Since free elevator cages are kept standing by according to preset conditions as described above in the prior-art elevator control apparatus, there arise problems that the free cages cannot be moved to optimum stand-by floors under the traffic state varying from time to time.